In general, in a silver halide photographic light-sensitive material, the incorporation of light absorbing compounds into silver halide emulsion layers or other hydrophilic colloid layers has so far been carried out in order to absorb light of a specific wavelength for the purposes of adjusting sensitivity, improving safelight safety, adjusting the color temperature of the light, preventing halation, and adjusting the sensitivity balance in multilayered color light-sensitive materials.
For example, when a silver halide photographic light-sensitive material, which comprises a support having provided thereon hydrophilic layers such as a light-sensitive silver halide emulsion layer, is subjected to an imagewise exposure in order to record an image in the light-sensitive silver halide emulsion layer, it is necessary to control the spectral composition of the light incident on the silver halide emulsion layer in order to improve the photographic sensitivity. In such cases, it is conventional to employ a method in which a dye capable of absorbing light of wavelengths undesired for the above silver halide emulsion layer is incorporated into hydrophilic colloid layers farther from the support than the above light-sensitive silver halide emulsion layer to form a filter layer, so that only light of the desired wavelengths is transmitted.
Further, a dye capable of absorbing light of the wavelength region in which silver halide is sensitive is used on some occasions for a silver halide emulsion layer for the purpose of preventing irradiation in order to improve the sharpness of the image.
In particular, silver halide photographic light-sensitive materials used for plate making processes, more specifically light-sensitive materials used in light rooms, contain a dye which absorbs UV rays and visible rays in a light-sensitive layer or a layer present between the light source and light-sensitive layer in order to increase safety under a safelight.
These colored layers consist of hydrophilic colloid in many cases, and a dye is usually incorporated into the layers for coloring. This dye is requested to satisfy the following conditions:
(1) The dye must have an appropriate spectral absorption consistent with the purpose for which it is being used.
(2) The dye must be photochemically inactive. That is, the dye must not have undesirable effects on the characteristics of a silver halide photographic layer in a chemical sense, such as, for example, a lowering of the sensitivity, a lowering of the image density, a reduction of the contrast, fogging, or degradation of the latent image.
(3) The dye must be capable of being readily bleached or dissolved and removed in the photographic processing steps without leaving harmful color on the processed photographic light-sensitive material.
Several methods are available for selectively coloring a specific hydrophilic colloid layer. The most frequently used method is one in which a hydrophilic polymer containing a group having a charge opposite to that of a dye ion is allowed to coexist as a mordant in a hydrophilic colloid layer and the dye is localized in a specific layer by the interaction of the mordant with the dye molecules (it is considered to be due to pulling by a charge and a hydrophobic bonding).
However, where a medium is used, a layer containing a dye contacts the other hydrophilic layers in a wet condition and this often permits a part of the dye to diffuse from the dye-containing layer to other layers. It is a matter of course that such diffusion of the dye depends on the chemical structure of the mordant but depends as well on the chemical structure of the dye used.
Where a high molecular weight mordant is used, the dye is particularly liable to remain on the light-sensitive material after photographic processing, particularly if the photographic processing is carried out in a shortened processing time. It is believed that this is because the bonding force of the mordant to the dye is significantly weakened in an alkaline solution such as a developing solution but the dye or a reversible decolored product of the dye remains in the layer containing the mordant due to the remaining, albeit weakened bonding force between the dye and the mordant.
As another means for holding a dye in a specific layer of a photographic light-sensitive layer, it has been proposed to permit the dyes to exist in the form of a solid dispersion, as disclosed in JP-A-56-12639 (the term "JP-A" as used herein means an unexamined published Japanese Patent Application), JP-A-55-155350, JP-A-55-155351, JP-A-52-92716, JP-A-63-197943, JP-A-63-27838, JP-A-64-40827, JP-A-2-110453, and JP-A-2-277045, EP-B1-0015601 and EP-A1-0276566, and Published International Patent Application W088/04794.
However, it has been observed that some kinds of dyes are still slow in terms of their discoloring speed in development processing even with these improved methods, and there has been a problem in that some dyes have tended to decompose under hot and humid conditions. In particular, there has been a problem that where many kinds of dyes are used according to the purposes, it is difficult to find out a combination of dyes by which various conditions are satisfied.